make authentication good for *2 weeks* instead of one. closes #543

lib/configuration.js

@@ -83,7 +83,7 @@ g_configs.production = {
     create_schema: true
   },
   bcrypt_work_factor: 12,
-  authentication_duration_ms: (7 * 24 * 60 * 60 * 1000),
+  authentication_duration_ms: (2 * 7 * 24 * 60 * 60 * 1000),
   certificate_validity_ms: (24 * 60 * 60 * 1000),
   min_time_between_emails_ms: (60 * 1000)
 };